Yan Weiming, Long Pan, Chen Tao, Liu Wei, Yao Lu, Ren Ze, Li Xiangqian, Wang Jiancong, Xue Junhui, Tao Ye, Zhang Lei, Zhang Zuoming
Department of Clinical Medicine, Faculty of Aerospace Medicine, Key Laboratory of Aerospace Medicine of the National Education Ministry, The Fourth Military Medical University, Xi'an, China.
Medical Experiment Center, Shaanxi University of Chinese Medicine, Shiji Ave., Xi'an-Xianyang New Economic Zone, Xi'an, China.
Cell Physiol Biochem. 2018;47(5):1883-1897. doi: 10.1159/000491068. Epub 2018 Jun 29.
BACKGROUND/AIMS: Our laboratory discovered a Kunming mouse with enormous electroretinogram (ERG) defects. Its auditory brainstem response (ABR) threshold was significantly elevated and closely resembled the features of Usher syndrome (USH). This study sought to cross these USH-like mice (named KMush/ush mice) with CBA/CaJ mice to establish recombinant inbred strains and identify their phenotypes and genotypes.
KMush/ush mice were crossed with CBA/CaJ mice to establish inbred strains by sibling mating. ERG, ABR, ocular fundus morphology, histological examinations of the retina and inner ear, quantitative real-time polymerase chain reaction, western blotting, and exon sequencing were performed to assess the phenotypes and genotypes of the offspring strains.
The F1 hybrids from crossing KMush/ush and CBA/CaJ mice had normal ERG and ABR responses. The F2 offspring from intercrossing the F1 mice showed a segregation of the retinitis pigmentosa (RP) and hearing loss phenotypes. The CBA-1ush/ush mice had an RP phenotype that was characterized by a vanished ERG waveform and loss of the outer nuclear layer. Their Pde6b gene had a nonsense mutation that resulted in the failure of protein production in western blotting. However, the ABR threshold of this strain of mice was normal. The CBA-2ush/ush mice had normal retinal function and architecture. Their ABR threshold was increased, with a dramatic degeneration of the stereocilia bundles in the outer hair cells of the inner ear. Whole exome sequencing and exon sequencing revealed a deletion of one base pair in exon 31 of the Adgrv1 gene, which would result in the premature termination of protein encoding. The level of Adgrv1 mRNA was reduced in the CBA-2ush/ush mice. The CBA-3ush/ush mice had phenotypes of RP, elevated ABR threshold, and degeneration of the stereocilia bundles in the outer hair cells. They were closely associated with the nonsense mutations of Pde6b and Adgrv1, respectively.
We isolated a mouse strain with hearing loss from inbred mice with retinal degeneration and established it as a recombinant inbred strain with a spontaneous mutation in Adgrv1, the human Usher syndrome 2C gene. The retinal degeneration was cause by a mutation in Pde6b, while the hearing loss was caused by a mutation in Adgrv1.
背景/目的：我们实验室发现了一只昆明小鼠，其视网膜电图（ERG）存在巨大缺陷。它的听觉脑干反应（ABR）阈值显著升高，与Usher综合征（USH）的特征极为相似。本研究旨在将这些USH样小鼠（命名为KMush/ush小鼠）与CBA/CaJ小鼠杂交，以建立重组近交系，并鉴定它们的表型和基因型。
将KMush/ush小鼠与CBA/CaJ小鼠杂交，通过同胞交配建立近交系。进行ERG、ABR、眼底形态学、视网膜和内耳组织学检查、定量实时聚合酶链反应、蛋白质免疫印迹法以及外显子测序，以评估子代品系的表型和基因型。
KMush/ush和CBA/CaJ小鼠杂交产生的F1代杂种具有正常的ERG和ABR反应。F1代小鼠相互杂交产生的F2代后代出现了视网膜色素变性（RP）和听力损失表型的分离。CBA-1ush/ush小鼠具有RP表型，其特征为ERG波形消失和外核层缺失。它们的Pde6b基因存在无义突变，导致蛋白质免疫印迹法中无法产生蛋白质。然而，该品系小鼠的ABR阈值正常。CBA-2ush/ush小鼠具有正常的视网膜功能和结构。它们的ABR阈值升高，内耳外毛细胞的静纤毛束严重退化。全外显子测序和外显子测序显示Adgrv1基因第31外显子缺失一个碱基对，这将导致蛋白质编码提前终止。CBA-2ush/ush小鼠中Adgrv1 mRNA水平降低。CBA-3ush/ush小鼠具有RP、ABR阈值升高和外毛细胞静纤毛束退化的表型。它们分别与Pde6b和Adgrv1的无义突变密切相关。
我们从患有视网膜变性的近交系小鼠中分离出一种听力损失小鼠品系，并将其建立为在人类USH综合征2C基因Adgrv1中存在自发突变的重组近交系。视网膜变性是由Pde6b突变引起的，而听力损失是由Adgrv1突变引起的。
